1ORX:
reference: Linearization of a naturally occurring circular protein maintains structure but eliminates hemolytic activity., Barry DG, Daly NL, Clark RJ, Sando L, Craik DJ, Biochemistry 2003 Jun 10;42(22):6688-95. PMID: 12779323

This OCA Structure page
uses Jmol, developed by the Jmol Development Team (documentation).